AIM: The aim of this study was to assess the effects of long-term physical exercise on peripheral nerve using both nerve conduction study (NCS) and ultrasonography (US).METHODS: The authors measured nerve conduction study and ultrasonography in 15 male (mean, 20±1.5 years) handball players and 13 male (mean, 21.3±1.9 years) control subjects. Cross-sectional area of the median nerve was evaluated using ultrasonography at the carpal tunnel and 6 cm proximal to the wrist, and the ulnar nerve at 6 cm proximal to the wrist crease, 2 cm proximal to the medial epicondyle, the epicondyle, and 2 cm distal to epicondyle.RESULTS: US shows significantly increased cross-sectional area of both median and ulnar nerve in the players compared with that in the controls, and the latency times in both nerves were significantly delayed in the players compared with that in the controls. Cross-sectional area of the median nerve showed a significant correlation with latency (r=0.330, P<0.01).CONCLUSION: This study suggests that the players have a tendency toward having both median and ulnar motor nerve damage in the wrist or elbow region although they are asymptomatic.